ITExpo East 2011: NGC-02 “The Next Generation of Voice over WLAN”

I will be moderating this panel at IT Expo in Miami on February 2nd at 10:00 am.

Voice over WLAN has been deployed in enterprise applications for years, but has yet to reach mainstream adoption (beyond vertical markets). With technologies like mobile UC, 802.11n, fixed-mobile convergence and VoIP for smartphones raising awareness/demand, there are a number of vendors poised to address market needs by introducing new and innovative devices. This session will look at what industries have already adopted VoWLAN and why – and what benefits they have achieved, as well as the technology trends that make VoWLAN possible.

The panelists are:

  • Russell Knister, Sr. Director, Business Development & Product Marketing, Motorola Solutions
  • Ben Guderian, VP Applications and Ecosystem, Polycom
  • Carlos Torales, Cisco Systems, Inc.

All three of these companies have a venerable history in enterprise Wi-Fi phones; the two original pioneers of enterprise Voice over Wireless LAN were Symbol and Spectralink, which Motorola and Polycom acquired respectively in 2006 and 2007. Cisco announced a Wi-Fi handset (the 7920) to complement their Cisco CallManager in 2003. But the category has obstinately remained a niche for almost a decade.

It has been clear from the outset that cell phones would get Wi-Fi, and it would be redundant to have dedicated Wi-Fi phones. And of course, now that has come to pass. The advent of the iPhone with Wi-Fi in 2007 subdued the objections of the wireless carriers to Wi-Fi and knocked the phone OEMs off the fence. By 2010 you couldn’t really call a phone without Wi-Fi a smartphone, and feature phones aren’t far behind.

So this session will be very interesting, answering questions about why enterprise voice over Wi-Fi has been so confined, and why that will no longer be the case.

Sharing Wi-Fi Update

Back in February 2009 I wrote about how Atheros’ new chip made it possible for a phone to act as a Wi-Fi hotspot. A couple of months later, David Pogue wrote in the New York Times about a standalone device to do the same thing, the Novatel MiFi 2200. The MiFi is a Wi-Fi access point with a direct connection to the Internet over a cellular data channel. So you can have “a personal Wi-Fi bubble, a private hot spot, that follows you everywhere you go.”

The type of technology that Atheros announced at the beginning of 2009 was put on a standards track at the end of 2009; the “Wi-Fi Direct” standard was launched in October 2010. So far about 25 products have been certified. Two phones have already been announced with Wi-Fi Direct built-in: the Samsung Galaxy S and the LG Optimus Black.

Everybody has a cell phone, so if a cell phone can act as a MiFi, why do you need a MiFi? It’s another by-product of the dysfunctional billing model of the mobile network operators. If they simply bit the bullet and charged à la carte by the gigabyte, they would be happy to encourage you to use as many devices as possible through your phone.

WiFi Direct may force a change in the way that network operators bill. It is such a compelling benefit to consumers, and so trivial to implement for the phone makers, that the mobile network operators may not be able to hold it back.

So if this capability proliferates into all cell phones, we will be able to use Wi-Fi-only tablets and laptops wherever we are. This seems to be bad news for Novatel’s MiFi and for cellular modems in laptops. Which leads to another twist: Qualcomm’s Gobi is by far the leading cellular modem for laptops, and Qualcomm just announced that it is acquiring Atheros.

Third Generation WLAN Architectures

Aerohive claims to be the first example of a third-generation Wireless LAN architecture.

  • The first generation was the autonomous access point.
  • The second generation was the wireless switch, or controller-based WLAN architecture.
  • The third generation is a controller-less architecture.

The move from the first generation to the second was driven by enterprise networking needs. Enterprises need greater control and manageability than smaller deployments. First generation autonomous access points didn’t have the processing power to handle the demands of greater network control, so a separate category of device was a natural solution: in the second generation architecture, “thin” access points did all the real-time work, and delegated the less time-sensitive processing to powerful central controllers.

Now the technology transition to 802.11n enables higher capacity wireless networks with better coverage. This allows enterprises to expand the role of wireless in their networks, from convenience to an alternative access layer. This in turn further increases the capacity, performance and reliability demands on the WLAN.

Aerohive believes this generational change in technology and market requires a corresponding generational change in system architecture. A fundamental technology driver for 802.11n, the ever-increasing processing bang-for-the-buck yielded by Moore’s law, also yields sufficient low-cost processing power to move the control functions from central controllers back to the access points. Aerohive aspires to lead the enterprise Wi-Fi market into this new architecture generation.

Superficially, getting rid of the controller looks like a return to the first generation architecture. But an architecture with all the benefits of a controller-based WLAN, only without a controller, requires a sophisticated suite of protocols by which the smart access points can coordinate with each other. Aerohive claims to have developed such a protocol suite.

The original controller-based architectures used the controller for all network traffic: the management plane, the control plane and the data plane. The bulk of network traffic is on the data plane, so bottlenecks there do more damage than on the other planes. So modern controller-based architectures have “hybrid” access points that handle the data plane, leaving only the control and management planes to the controller device (Aerohive’s architect, Devin Akin, says:, “distributed data forwarding at Layer-2 isn’t news, as every other vendor can do this.”) Aerohive’s third generation architecture takes it to the next step and distributes control plane handling as well, leaving only the management function centralized, and that’s just software on a generic server.

Aerohive contends that controller-based architectures are expensive, poorly scalable, unreliable, hard to deploy and not needed. A controller-based architecture is more expensive than a controller-less one, because controllers aren’t free (Aerohive charges the same for its APs as other vendors do for their thin ones: under $700 for a 2×2 MIMO dual-band 802.11n device). It is not scalable because the controller constitutes a bottleneck. It is not reliable because a controller is a single point of failure, and it is not needed because processing power is now so cheap that all the functions of the controller can be put into each AP, and given the right system design, the APs can coordinate with each other without the need for centralized control.

Distributing control in this way is considerably more difficult than distributing data forwarding. Control plane functions include all the security features of the WLAN, like authentication and admission, multiple VLANs and intrusion detection (WIPS). Greg Taylor, wireless LAN services practice lead for the Professional Services Organization of BT in North America says “The number one benefit [of a controller-based architecture] is security,” so a controller-less solution has to reassure customers that their vulnerability will not be increased. According to Dr. Amit Sinha, Chief Technology Officer at Motorola Enterprise Networking and Communications, other functions handled by controllers include “firewall, QoS, L2/L3 roaming, WIPS, AAA, site survivability, DHCP, dynamic RF management, firmware and configuration management, load balancing, statistics aggregation, etc.”

You can download a comprehensive white paper describing Aerohive’s architecture here.

Motorola recently validated Aerohive’s vision, announcing a similar architecture, described here.

Here’s another perspective on this topic.

Dual Mode Phone Trends Update 4

We are half way through the year, so it’s time for another look at Wi-Fi phone certifications. Three things jump out this time. First, a leap in the number of Wi-Fi phone models in the second quarter of 2010. Second, the arrival of 802.11n in handsets, and third Samsung’s market-leading commitment to 802.11n. According to Rethink Wireless “Samsung’s share of the smartphone market was only about 5% in Q1 but it aims to increase this to almost 15% by year end.” Samsung Wi-Fi-certified a total of 73 dual mode phones in the first six months of 2010, three times as many as second place LG with 23. In the 11n category, Samsung’s lead was even more dominating: its 40 certifications were ten times either of the second place OEMs.

Here is a chart of dual mode phones certified with the Wi-Fi Alliance from 2008 to June 30th 2010. We usually do this chart stacked, but side-by-side gives a clearer comparison between feature phones and smart phones. Note that up to the middle of 2009, smart phones outpaced feature phones, but then it switched. This is a natural progression of Wi-Fi into the mass market, but may also be exaggerated by a quirk of reporting: of HTC’s 17 certifications in the first half of 2010, it only categorized one as a smart phone.
Dual mode phones by quarter 2008-2010

The chart below shows the growth of 802.11n. It starts in January 2010 because only one 11n phone was certified in 2009, at the end of December. As you can see, the growth is strong. I anticipate that practically all new dual mode phone certifications will be for 802.11n by the end of 2010.

802.11n phones 2010 by month

Below is the same chart sliced by manufacturer instead of by month. The iPhone is missing because it wasn’t certified until July, and the iPad is missing because it’s not a phone. With only one 802.11n phone, Nokia has become a technology laggard, at least in this respect. The RIM Pearl 8100/8105 certifications are the only ones with STBC, an important feature for phones because it improves rate at distance. All the major chips (except those from TI) support STBC, so the phone OEMs must be either leaving it disabled or just not bothering to certify for it.

802.11n phones 2010 by manufacturer

Wi-Fi for Mice and Keyboards

A while back the Wi-Fi Alliance announced a new certification program, Wi-Fi Direct, which enables a PC to connect directly with other Wi-Fi devices without having to go through an Access Point.

The Wi-Fi certification process for Wi-Fi Direct is scheduled to be launched by the end of 2010, but there are already two pre-standard implementations of this concept, My Wi-Fi, an Intel product which ships in Centrino 2 systems, and Wireless Hosted Network which ships in all versions of Windows 7.

The Wi-Fi Direct driver makes a single Wi-Fi adapter on the PC look like two to the operating system: one ordinary one that associates with a regular Access Point, and a second acting as a “Virtual Access Point.” The virtual access point (Microsoft calls it a “SoftAP”) actually runs inside the Wi-Fi driver on the PC (labeled WPAN I/F in the Intel diagram below).

To the outside world the Wi-Fi adapter also looks like two devices, each with its own MAC address: one the PC just like without Wi-Fi Direct, and the other an access point. Devices that associate with that access point join the PC’s PAN (Personal Area Network).

This yields several benefits in various use cases.

I wrote a couple of years ago about how a company called Ozmo planned to use a Wi-Fi PAN to connect peripherals to PCs, replacing Bluetooth and proprietary wireless technologies. That plan has now come to fruition. Earlier this month Ozmo announced that it had received $10.8 million in additional funding, and this week it announced two major customers: Primax, a leading ODM of wireless mice, and NMB Technologies, a leading ODM of wireless keyboards.

Here’s a slide from one of their promotional presentations giving a comparison with Bluetooth and proprietary technologies:
Comparison of Ozmo's low power Wi-Fi technology with Bluetooth and proprietary solutions for Human Interface Devices (HIDs)

The essence of Ozmo’s approach is low cost, multi-device, low bandwidth and low power consumption. Wi-Fi Direct has another use case that is high bandwidth, with no requirement for low power.

If you want to stream video from your PC to a monitor using traditional Wi-Fi (“infrastructure mode”) each packet goes from the PC to the access point, then from the access point to the TV, so it occupies the spectrum twice for each packet. Wi-Fi Direct effectively doubles the available throughput, since each packet flies through the ether only once, directly from the PC to the TV. But it actually does better than that. Supposing the PC and the TV are in the same room, but the access point is in a different room, the PC can transmit at much lower power. Another similar Wi-Fi Direct session can then happen in another room in the house. Without Wi-Fi direct the two sessions would have to share the access point, taking turns to use the spectrum. So we get increased aggregate throughput both from halving the number of packet transmissions, and from allowing simultaneous use of the spectrum by multiple sessions (if they are far enough apart).

A Wi-Fi buff would point out that you can already do all this with ad-hoc mode, but Wi-Fi Direct purports to be usable by mortals, and to work interoperably, neither of which could be said for ad-hoc mode until recently. In January Infinitec announced a new point-to-point video streaming product that claims to be easy to use and universally interoperable, that Engadget implies uses ad-hoc mode, though Google can’t find the words “ad hoc” on the Infinitec website.

Between the bandwidth extremes of mice and TVs, lie numerous other potential uses, like headsets (which Ozmo also supports); syncing phones, cameras and media players; and wireless printers.

Wi-Fi Ubiquity

ABI came out with a press release last week saying that 770 million Wi-Fi chips will ship in 2010. This is an amazing number. Where are they all going? Fortunately ABI included a bar-chart with this information in the press release. Here it is (click on it for a full-size view):

Wi-Fi chip shipments worldwide. Source: ABI

The y axis isn’t labeled, but the divisions appear to be roughly 200 million units.

This year shows roughly equal shipments going to phones, mobile PCs, and everything else. There is no category of Access Points, so presumably less of those are sold than “pure VoWi-Fi handsets.” I find this surprising, since I expect the category of pure VoWi-Fi handsets to remain moribund. Gigaset, which makes an excellent cordless handset for VoIP, stopped using Wi-Fi and went over to DECT because of its superior characteristics for this application.

There is also no listing for tablet PCs, a category set to boom; they must be subsumed under MIDs (Mobile Internet Devices).

The chart shows the portable music player category growing vigorously through 2015. iPod unit sales were down 8% year on year in 1Q10, and pretty much stagnant since 2007. ABI must be thinking that even with unit sales dropping, the attach rate of Wi-Fi will soar.

The category of “Computer Peripherals” will probably grow faster than ABI seems to anticipate. Wireless keyboards and mice use either Bluetooth or proprietary radios currently, but the new Wi-Fi alliance specification “Wi-Fi Direct” will change that. Ozmo is aiming to use Wi-Fi to improve battery life in mice and keyboards two to three-fold. Since all laptops, most all-in-one PCs and many regular desktops already have Wi-Fi built-in (that’s at least double the Bluetooth attach rate) this may be an attractive proposition for the makers (and purchasers) of wireless mice and keyboards. Booming sales of tablet PCs may further boost sales of wireless keyboards and mice.

Samsung GT-S8500 is first with 11n, BT 3.0 certifications

Engadget reports that the Samsung GT-S8500 is the first phone to support Bluetooth 3.0. A look at the Wi-Fi Alliance website reveals that it was also the first feature phone to gain 802.11n certification.

The certificate is dated December 28th 2009, the same date that the first smartphone was certified for 802.11n – the LG Veri/VS750. The VS750 Wi-Fi appears to be more advanced than the Samsung, since it is certified for short guard interval and WMM Power Save.

While these are the first phones to gain Wi-Fi certification for 802.11n, they may not be the first to market.

VoIP over the 3G data channel comes to the iPhone

I discussed last September how AT&T was considering opening up the 3G data channel to third party voice applications like Skype. According to Rethink Wireless, Steve Jobs mentioned in passing at this week’s iPad extravaganza that it is now a done deal.

Rethink mentions iCall and Skype as beneficiaries. Another notable one is Fring. Google Voice is not yet in this category, since it uses the cellular voice channel rather than the data channel, so it is not strictly speaking VoIP; the same applies to Skype for the iPhone.

According to Boaz Zilberman, Chief Architect at Fring, the Fring iPhone client needed no changes to implement VoIP on the 3G data channel. It was simply a matter of reprogramming the Fring servers to not block it. Apple also required a change to Fring’s customer license agreements, requiring the customer to use this feature only if permitted by his service provider. AT&T now allows it, but non-US carriers may have different policies.

Boaz also mentioned some interesting points about VoIP on the 3G data channel compared with EDGE/GPRS and Wi-Fi. He said that Fring only uses the codecs built in to handsets to avoid the battery drain of software codecs. He said that his preferred codec is AMR-NB; he feels the bandwidth constraints and packet loss inherent in wireless communications negate the audio quality benefits of wideband codecs. 3G data calls often sound better than Wi-Fi calls – the increased latency (100 ms additional round-trip according to Boaz) is balanced by reduced packet loss. 20% of Fring’s calls run on GPRS/EDGE, where the latency is even greater than on 3G; total round trip latency on a GPRS VoIP call is 400-500ms according to Boaz.

As for handsets, Boaz says that Symbian phones are best suited for VoIP, the Nokia N97 being the current champion. Windows Mobile has poor audio path support in its APIs. The iPhone’s greatest advantage is its user interface, it’s disadvantages are lack of background execution and lack of camera APIs. Android is fragmented: each Android device requires different programming to implement VoIP.

Top ten uses for an Internet Tablet/Web Slate

The tablet wars are imminent, with Microsoft, Google and Apple breaking out their big guns. Here’s what you will be doing with yours later this year:

  1. Internet browser of course: think iPhone experience with a bigger screen. It will be super-fast with 802.11n in your home, and somewhat slower when you are out and about, tethering to your cell phone for wide-area connectivity. You don’t need a cellular connection in the Internet Tablet itself, though the cellcos wish you would.
  2. TV accessory: treat it as a personal picture-in-picture display. View the program guide without disturbing the other people watching the main screen. Use it for voting on shows like American Idol. Use it as a remote to change channels and set up recordings.
  3. TV replacement: a 10 inch screen at two feet is the same relative size as a 50 inch screen at ten feet. Use it with Hulu and the other streaming video services.
  4. Video iPod, but with a much nicer screen. Say goodbye to portable DVD players.
  5. VideoPhone: some Internet Tablets will have hi-res user-facing cameras and high definition microphones and speakers: the perfect Skype phone to keep on your coffee table. How about on your fridge door for an always-on video connection to the grandparents? Or in a suitable charging base, a replacement office desk phone.
  6. Electronic picture frame: sure it’s overkill for such a trivial application, but when it’s not doing anything else, why not?
  7. eBook reader: maybe not in 2010, but as screen and power technology evolve the notion of a special-function eBook reader will become as quaint as a Wang word processor. (Never heard of a Wang word processor? I rest my case.)
  8. Home remote: take a look at AMX. This kind of top-of-the-line home control will be available to the masses. Set the thermostat, set the burglar alarm, look at the front door webcam when the doorbell rings…
  9. Game console: look at all the games for the iPhone. Many of them will work on Apple’s iSlate from day one. And you can bet there will be plenty of cool games for Android, and even Windows-based Internet Tablets.
  10. PND display: Google Maps on the iPhone is miraculously good, but it’s not perfect. The display is way too small for effective in-car navigation. It’s possible that some Internet Tablets will have GPS chips in them (GPS only adds a few dollars to the bill of materials), but for this application there’s no need. Tether it to your cell phone for the Internet connectivity and the GPS, and use the tablet for display and input only.

2010 will be the year of the Internet Tablet. The industry has pretty much converged on the form factor: ten-inch-plus screen, touch interface, Wi-Fi connectivity. What’s a little more up in the air are minor details that will provide differentiation, like cellular connectivity, cameras, speakers and microphones. Apple will jump-start the category, but there will quickly be a slew of contenders at sub-$200 price points.

Several technology advances have converged to make now the right time. Low-cost, low energy ARM processors like the Qualcomm Snapdragon have enough processing muscle to drive PC-scale applications, and their pricing piggy-backs on the manufacturing scale of phones. 802.11n is fast enough for responsive web-based applications and HD video streaming. LCD screens continue to get cheaper. Personal Wi-Fi networks enable tethering and wireless keyboards for when you need them.

This also the perfect form factor for grade school kids. Once the screen resolutions get high enough books will disappear almost overnight. No more backs bent under packs laden with schoolbooks. Just this.

First 802.11n handset spotted in the wild – what took so long?

The fall 2009 crop of ultimate smartphones looks more penultimate to me, with its lack of 11n. But a handset with 802.11n has come in under the wire for 2009. Not officially, but actually. Slashgear reports a hack that kicks the Wi-Fi chip in the HTC HD2 phone into 11n mode. And the first ultimate smartphone of 2010, the HTC Google Nexus One is also rumored to support 802.11n.

These are the drops before the deluge. Questions to chip suppliers have elicited mild surprise that there are still no Wi-Fi Alliance certifications for handsets with 802.11n. All the flagship chips from all the handset Wi-Fi chipmakers are 802.11n. Broadcom is already shipping volumes of its BCM4329 11n combo chip to Apple for the iTouch (and I would guess the new Apple tablet), though the 3GS still sports the older BCM4325.

Some fear that 802.11n is a relative power hog, and will flatten your battery. For example, a GSMArena report on the HD2 hack says:

There are several good reasons why Wi-Fi 802.11n hasn’t made its way into mobile phones hardware just yet. Increased power consumption is just not worth it if the speed will be limited by other factors such as under-powered CPU or slow-memory…

But is it true that 802.11n increases power consumption at a system level? In some cases it may be: the Slashgear report linked above says: “some users have reported significant increases in battery consumption when the higher-speed wireless is switched on.”

This reality appears to contradict the opinion of one of the most knowledgeable engineers in the Wi-Fi industry, Bill McFarland, CTO at Atheros, who says:

The important metric here is the energy-per-bit transferred, which is the average power consumption divided by the average data rate. This energy can be measured in nanojoules (nJ) per bit transferred, and is the metric to determine how long a battery will last while doing tasks such as VoIP, video transmissions, or file transfers.

For example, Table 1 shows that for 802.11g the data rate is 22 Mbps and the corresponding receive power-consumption average is around 140 mW. While actively receiving, the energy consumed in receiving each bit is about 6.4 nJ. On the transmit side, the energy is about 20.4 nJ per bit.

Looking at these same cases for 802.11n, the data rate has gone up by almost a factor of 10, while power consumption has gone up by only a factor of 5, or in the transmit case, not even a factor of 3.

Thus, the energy efficiency in terms of nJ per bit is greater for 802.11n.

Here is his table that illustrates that point:
Effect of Data Rate on Power Consumption

Source: Wireless Net DesignLine 06/03/2008

The discrepancy between this theoretical superiority of 802.11n’s power efficiency, and the complaints from the field may be explained several ways. For example, the power efficiency may actually be better and the reports wrong. Or there may be some error in the particular implementation of 802.11n in the HD2 – a problem that led HTC to disable it for the initial shipments.

Either way, 2010 will be the year for 802.11n in handsets. I expect all dual-mode handset announcements in the latter part of the year to have 802.11n.

As to why it took so long, I don’t think it did, really. The chips only started shipping this year, and there is a manufacturing lag between chip and phone. I suppose a phone could have started shipping around the same time as the latest iTouch, which was September. But 3 months is not an egregious lag.